Hasan Hossain al-Haj was the second-most prominent Hezbollah commander to be killed in Syria after Imad Fayez Mughniyeh was killed by a car bomb in Damascus in 2008.

Rebel fighters from Al-Fath Army clash with the Syrian military May 19 in Mastouma, in Idlib city, Syria. Two Hezbollah commanders, including a senior leader, were killed in Idlib province Saturday and Tuesday, respectively, during a countrywide offensive by the Syrian military, which is backed by Russian airstrikes and Hezbollah militants. Photo by Radwan Homsy/UPI | License Photo

Hasan Hossain al-Haj, a senior commander in the Lebanese militant group, was killed Saturday amid a Syrian military offensive across the country. The Daily Star reports a second unidentified Hezbollah commander was killed Tuesday.

By August, government troops had been pushed into western Syria's Latakia province, home to the country's ruling Alawite minority, but a late-September intervention by Russian forces, which began conducting airstrikes on behalf of Assad, prompted the recent counter-attacks.

The Syrian Observatory for Human Rights, a Britain-based activist group monitoring the Syrian conflict, reported Tuesday at least seven Hezbollah fighters were killed during fighting in Hama province, south of Idlib, while 20 others were injured.

On Monday, supporters in Lebanon reportedly buried al-Haj, who was the second-most prominent Hezbollah commander killed in Syria since 2008, when Imad Fayez Mughniyeh was killed by a car bomb in Damascus.

Hezbollah, a Shia Arab militant group and political party in Lebanon, is considered a proxy force for Iran, one of Assad's primary allies, which trains and supports its fighters. Since 2012 the group has fought in Syria on behalf of Assad, who belongs to the Alawite sect associated with Shia Islam.